Is this a screw-in piece on the rear-view mirror?

[Hilljack68]

68 Coronet. My rear-view keeps moving as I drive, and this point here is the culprit. Does that ball-type piece screw into the stem? I haven't had a free moment to take it off (busy with firewood, and Christmas stuff), but I'm assuming it's a screw-in joint. Any insight?

 

[turbine68rt]

68 may have used both a threaded post and a splined push-on type as well. My original had the splined version and I got tired of the mirror falling down onto the console, so I found a screw-on in a junkyard many years ago and just replaced the post. Problem solved.